B) compound.
A compound is usually made up of different Elements, a compound is likely to have a melting point as well.
Answer:
25.2563 m/s
Explanation
This is the equation needed

So Just plug in!
I’m guessing is because she uses force to throw the ball, allowing the energy to move the person.
sorry if it’s not 100% correct
Answer:
0.41
Explanation:
A 49 N block has a mass of 5 kg:
49/9.8
A horizontal force of 50 N giving it an acceleration of 6 m/s^2 means that 30 N is taken up by the acceleration
This leaves 20 N to take care for friction. so the coefficient of friction is:
20/49 = 0.41.
If we consider our origin to be zero then if we walk 15m west then back 7m east our displacement would be the difference (since west and east are opposite directions to one another).
15m - 7m = 8m
And so, we are 8 meters away from our origin, thus our displacement is 8 meters.